Sorry, yeah it's in the reading of what I wrote.
You can only descend to the radar minimum altitude if the controller has given you a clearance to do so. "cleared for the ILS" is not a clearance to descend to radar minimums. Remember that under radar control the controller is responsible for terrain separation, but that doesn't absovle the good pilot from ensuring he is still terrain safe. This threw up questions for me several years ago when I started flying commercially. I asked the line trainers how I could justify descending below MSA whilst under radar control with no radar vectoring chart available to me. They couldn't come up with anything other than "you just have to trust them", which never really satisfied me.....anyhow off topic there.
Basically, if they give you a final vector to intercept the localiser, stay at the cleared altitude.
If you are flying a procedure, descend in accordance with the procedure once you have been cleared for the procedure. This applies even if you are under radar coverage. I refer to Alicante once again as a good example of this. Take a look at the approach and ILS-Zulu 10 plate for Alicante which shows it quite well. As you fly towards VILNA the minimum FL is FL80 (from the approach chart), with a minimum holding level of FL70 at VILNA. The controllers have you under radar, clear you down to FL70 (minimum radar vectoring altitude in the sector is 6000').
As you approach VILNA you are cleared for the ILS ZULU for runway 10. That is all they say. It is now up to the pilot to fly the procedure, even though you are being monitored on radar. We need to stay above FL70 going over VILNA and then descend in accordance with the procedure. From VILNA you fly a 20dme arc which has a minimum altitude of 5900', so we cross VILNA and start to descend to 5900', remembering to set the QNH!. You fly the arc to intercept the localiser and once established you follow the descend restrictions on the chart to ensure you step down over the mountains! 17.6d on the ILS descend from 5900' to 4200'. 14.6d descned to 3300'. At 9.8d you intercept the glideslope and descend to minimums.
Note that the protected area for a glideslope signal extends to 10nm, so at Alicante you are only just inside that when you intercept the glide at the lowest platform depicted on the chart. Indeed Alicante has NOTAMs about the protected areas for localiser and glideslope, reminding pilots of the maximum range where no interference has been checked. Often on pretty much straight in approaches (not Alicante) you are given a final vector and cleared for the approach. If you are outside 25nm the localiser signal is not guaranteed and if you arm the localiser and capture it the a/c will wander from left to right following this distorted signal. The best way to do it is to just fly along the localiser in HDG SEL until you are within the defined range and the signal appears stable.
So going back to Alicante runway 10, the controllers expect you to fly the procedure once cleared for it and to descend in accordance with it. You can stay above the minimum altitudes if you want, but must not go below them.
Can you see how this differs from say radar vectors? Here (in the UK) the controllers "radar control" you, giving you headings to steer and descent to altitudes to keep you terrain safe. They put you on an intercept heading and tell you to "report established" on the localiser. If they then clear you for descent on the glideslope you stay at the cleared altitude and intercept the glideslope before further descent. Why? Well if they vector you quite a way out, say 20nm and put you on an intercept on what basis are you taking it upon yourself to descned to a platform drawn on a chart which applies to a procedural approach? You may well be no where near the procedure at 20nm out, especially if it is designed to take you from a beacon on the airfield, outbound and then turn back inbound to establish on the ILS. What if the MSA is above the platform? You have to justify descending below MSA every time you do an approach, be it because you are visual, under radar control or on a procedure above procedure minima, or established on a let down aid such as ILS. So if a radar controller had you at his radar minima (below MSA), yet some distance out, you can't justify descending to a platform for a procedure that you are not on because he has told you that you are clear for the ILS. I would always stay at the cleared altitude until I had the justification to descend further safely.
I hope this helps.
PP