When entering turbulence, the classic procedure is to maintain pitch and power and let the aircraft just float with the updrafts and downdrafts, accepting minor departures from the assigned altitude (up to several hundred feet) and intervening with the controls only occasionally. Assuming that you were trimmed properly when entering the turbulence, you
don't touch the trim. Assuming that the power was properly set upon entering the turbulence, you
don't touch the power.
Gums:
It seems that AF447 came close to "breaking the stall", i.e. getting thrust greater than drag. Using the full movement of the THS could have been the key.
It was very unhelpful of the autotrim to run the THS all the way to 13, notwithstanding that the PF, inexplicably pulled back on the stick.