Only Senslar would have been able to get a good look at him, from below at least. Alevyth was standing against the wall on the opposite side of the square. From there he can only see Lazarus's signature gold encrusted armour. Then, he entered the fray, got blinded, and now that he can see, Lazarus is just entering the Cathedral. Makes sense?
BTW regarding Adelaide, you will see the finer points to her personality once you get to know her. She is the daughter of a famous warrior (hence the Swiftblade surname), who always wanted a son. She took on paladinhood in hopes of gaining her father's approval. Now she subconsciously sees her father in Lazarus, hence her affection. But that's all a spoiler i probably should not have given you