I think there is a Plumeria forum here on Garden Web

Wow, where do you keep it? inside?
I have one inside in container but it does not want to flower.

Outside in summer, inside in winter

Here is a link that might be useful: Plumeria

goes out in nice days during the winter for a few hours, spent cold days inside under lights. In march it went out for the summer (it was already starting to flower)

The yellow one was treated the same and it isn't flowering yet.