I am writing an academic paper for submission to a journal. One of my co-authors wrote the following:

Theorem Statement of the theorem

Proof of theorem We first show the following result

Lemma Statement of lemma used to prove the theorem

However, I think that it is more natural to present things in the following way:

Theorem Statement of the theorem

We first show the following result which is used to prove the theorem:

Lemma Statement of lemma used to prove the theorem

Proof of theorem blah blah

I understand that this is a subjective question so I am happy to mark this as community wiki if most people feel that it belongs there.