I bow to your superior knowledge of the A310 and A300-600 series. I recall your previous posts as to the (alleged) design limitations of these aircraft, and the reservations that you have expressed to designers and manufacturers.
Slats by their very nature are there to provide more lift at slow speed. So you could expect slats to be extended whenever the aircraft is in a slow flight regime. Take-off, initial climb out, approach, landing and go-around.
On lightning strikes. I have been struck maybe half a dozen times in twenty years, mostly whilst flying in the UK. In turn most of these strikes were from small innocuous cumulous clouds, and in most cases we were clear of the clouds themselves. Conversely I have been caught in proper equatorial CB's with lightening all around, and survived shaken, stirred but never struck.
So to try to answer your last question. You could be operating your aircraft near an airport, with the slats and flaps extended. And you could easily find yourself being struck by lightning from that small cumulous cloud, without actually being physically in it.
Some years ago there were a series of photographs on PPRuNe showing a B747 climbing out of an Asian airport (I forget which one) and it is quite clearly being struck by lightning!