You can talk to Lumia about getting a tour with Eira before speaking with Annika who suggested that in the first place

[Bubballs]

Basically what it says on the tin. If you don't speak with Annika after finishing the Shadows over the Sun quest and go directly to Lumia to talk, the option to talk to her about Eira and the tour is there despite you having never been given a reason to ask about her