Approach Clearance vs. Platform Altitude
To answer the question accurately, you have to look at the specific approach plate. Generally (almost always) the glide slope intercept altitude displayed is the minimum. So, you can intercept farther out from the runway at a higher altitude...that's ok.
But, in very few cases the published glide slope intercept altitude is shown as "Mandatory". In this case, one would be obliged to maintain the last assigned altitude until established on a published segment of the approach...THEN, descend to the mandatory glide slope intercept altitude for the actual glide slope intercept.
In either case...it's important to remember that descent from the last assigned altitude cannot commence prior to becoming established on a published segment of the approach.
What constitutes 'established'? With regard to the localizer, you are considered established when the needle is alive. In some cases, you will be flying an intermediate segment prior to localizer intercept. Again, if the needle is alive, you're good enough to be considered established. You can then begin descent to the minimum altitude for that segment (assuming clearance to do so).
With regard to the Airbus, you have to make the aircraft do what you want it to do...not what is programed by the engineers. However, keep in mind when the winds at your altitude are in excess of a ten knot tailwind, the decelerated approach technique is not allowed. (FCOM 3.03.18 P1). In this case, you must intercept the glide path as per the Airbus profile (or your airline's SOP).
I hope this helps....