"I'm Lottie, and Mum is Mum!" Clearly this is the correct answer when non-Changelings are involved. Louise is Mum.

"Louise Beck, actually. It's good to meet you. ...When and where should we meet? We haven't actually been to the place that they told us we could stay in yet, and," Lottie will probably crash sometime soon, and you don't want a tired and cranky three year old on such a journey, "we should probably eat and sleep some first, so... do you think tomorrow will be soon enough?"