I'm about to go on my first dinner date and would like to know the proper etiquette for handling the donation.  Is it appropriate to discretely provide an envelope upon meeting or should I have it waiting back in the room?  Should I ask her what her preference is?  The last thing I want is to end up in an awkward situation.  Thanks everyone!

Are you and the lady meeting at your room first and then going to dinner?If so you could have the envelope out in a visible area that she can see when she walks in.
If you are meeting at the restaurant first just leave the envelope in the room.
When I do dinner dates I always meet first in the room so never an issue.
Does she have on her website mention of where she wants the envelope placed?If not I would just meet in your room first give her the envelope and then have a fantastic dinner.
Have fun!

preference, as the others mentioned check her website. I suggest that if you are meeting at the restaurant first, then a cute gift bag with the envelope inside is another way.

Only if you can't figure out what she prefers. Good luck and have a great time!

With card & donation inside if you meet in public.

If it's not already listed on her website.  

Yes, this happened. Took everything I had to pull out of my "WTF are you serious" mode.

I always have the lady come to my room before we go out to dinner.  That way, the donation is taken care of and she can leave her supplies, etc. in the room and not have to carry them to the restaurant.  Sometimes, we also plan BCD time before dinner, so everything works out fine

If you're meeting first in the restaurant place it in a gift bag or magazine, don't leave it in the room. Paying a lady should be done within the first few minutes of meeting as it assures her that the business aspect is taken care of and you can both relax and have a good time.