I just lollipopped one a week into flower and it didn't even notice. I recommend pruning for creating better bud sites and increasing airflow. I don't recommend full on lollipopping... yet. I'll let you know!
Yeah, i even top them, do some lst and just about any technique, you can defenitly do it, good luck and stay lit growmie, just only prune necessary leafs.
It's usually not recommended, as the stress you can cause with pruning will slow down the overall development of the plant, affecting its final outcome.