try jiggling it? or if the lid comes apart from the hinge assembly remove it and see if you get more leverage on the hinge to move it back to release the mechanism. or if you can bend up a paperclip and push the locking mechanism to the release position... not too sure how you would accomplish the last one but it's a thought.
Lower it slowly. When mine gets stuck this is what I do and it works. If you try to man handle it down it will get stuck. Cold temps do a number on things.
Had this recently.. There IS a non dealer related fix! There is a replaceable cover piece that has prongs that break off and cause the lid to be stuck up...
The dealers will barely help but the item retails for $25-39 and solves the stuck issue... It is called the ' armrest repair kit' part number is 1k0898207