I know it doesn't matter much in the scheme of things because obviously Katherine/Elijah aren't going to happen as long as they are on two separate shows and Nina Dobrev won't be joining The Originals as Katherine, but Elijah didn't abandon Katherine as she thought he had in the final episodes of The Vampire Diaries and over the summer break!
Klaus daggered Elijah the morning after he left Mystic Falls. Katherine thought he hadn't called or returned period, thus abandoning her, but that wasn't the case. We know that now for sure, but Katherine doesn't. I wonder if that will come up once he's undaggered. Hmmm. Again, I know it doesn't really matter, but I like that it at least explains why Elijah hasn't been there at all for Katherine in this desperate time of need for her.