Penetrating Oil!
Stay back, use a breaker bar,
and you'll probably need more than a few turns.
Earlier models had fine threads, and twice I have had the block in the lower control arm lose all its threads and spit the bolt out with great force, once WHILE I was making an adjustment and the car slammed down on that side,
Fortunately I was way back and not injured, but it was very scary.
I changed the block and bolt to a coarse thread, but these are harder to turn adjusting, because the mechanical advantage is less.
It will be easier to raise the height if you take weight off the wheel and just work against the torsion bar loading.
It will also be safer, but I believe you probably already have the coarse thread bolt/block.