Have completed charging lexicon and gotten the elder scroll but when returning via elevator to skyrim my screen freezes and images fade in and out at elevator gate. Tried reload from last saved but upon using elevator it does the same thing. My only choice is to exit to desktop. I am at level 20 with no mods added. Has anyone experienced this? Solutions?

Odd. Assuming the quests triggered correctly I think the Alduin's Base quest has already started. I don't think there are any specific triggers that occur past the elevator, so I suppose you can try bumping up the console, inputting coc HighHrothgarEntrance and going back to the Throat of the World from there. It's not ideal but it should at least keep you going. As a safety precaution, I would create a new save slot immediately after teleporting.

Have you tried going back out the way you came in? The problem may be just with that elevator. It's only a short cut if it works!