This week's Weekend Workout (31-08-2018) has a question and answer as detailed below.
The translation for 'we arrived' is given in the imparfait but surely it should be in the Passé composé as they arrived only 'once' and not as the imparfait implies 'used to arrive' meaning they arrived on a regular basis i.e. more than just on the one occasion.
Could you please explain.
When we arrived in the changing rooms,
Quand nous arrivions dans les vestiaires,