pathfinder – Spells belonging to several schools

The new arcane elementary schools do not mention anything about the spells that belong to which schools. So, in the event that a spell appears in both your elementary school and your opposition school, how do you decide how to treat it?

Sirocco is a good example.

School evocation [air, fire]; Elementary school air 6, fire 6, wood 4

So, do I use school tags or elementary school tags? If I choose Air and my opposition school is Fire, what should I do?