Is Lorazepam good for sleep?

Yes, but don't use it every night.

Actually, just having read on another thread (which I am finding very confusing) where you said, "I take it (Ativan), but it didnīt work no more for me", then no. You have developed tolerance to benzodiazepines so there is no point swapping one for another. Unless you want to start the vicious cycle of ever-increasing doses, you need to cut back on their use.