[The problem here is that...he'd met Lan Wangji as Xia Sini and he was not going to talk about the disaster that was his meeting with Wei Wuxian (assuming, they even got around to introducing themselves the thread is on going).

Then again, he was an elder of the sect, would it be so weird to have asked about the people a junior disciple met?]

I have heard of the Second Young Master Lan. His sect isn't one I have ever heard of. It seems we come from different worlds.