while pulling on the handle enough to unlatch the door, pull on the top by the roof to open it.
CHURCH! They should've printed that in the owner's manual.
By 95 GM had figured out how to make a vertical W-Body coupe door handle that wouldn't break off every-other year, so it isn't too big a deal if you tug on the handle the entire time you're opening the door.
What you should do is grab up a can of Jig-A-Loo, spray some on a rag, open your doors, and wipe down the weatherstripping with it. Also, clean off the mating surface on the door itself where the weatherstrip bumps against.
Other than that, you could always invest in a remote start system, and warm the car up for a few minutes before you climb in. That'll thaw your doors out a bit.