I know. It is confusing. I once had a conversation w/ a patronne in which she spoke French and I answered in Swahili. It was quite amusing :)

As for your sentence, there are a couple of ways you could write it, but I think the best choice is:

'He then (or 'Then he'--my preference) remembered that on their wedding night, when he penetrated Lubie, such and such happened...

Sound good?