Your barking up the wrong tree if your looking for psychedelic effects from this particular drug. You could possible take a large enough dose to become completely detached from reality, but that can be done with ANYTHING. I'll add also, seconding what others have said, benzos are best enjoyed sublingually. I don't have science to back this up, but I don't believe that lorazepam is water soluble, and for this reason won't be readily absorbed by the mucous membranes in your sinuses.
Swallow it, or put it under your tongue man.
Kunmo: Sick avatar by the way, Disraeli Gears is probably my favorite work of Cream!