What do you do if there is a subjunctive trigger that is followed by the imperfect tense?
There is in fact an imperfect subjunctive, however it is rarely used and can only normally be found in technical pieces of literature or criticism. As a result, the present subjunctive is what would be needed here.
ZL
Related French A Level answers
All answers ▸What is the subjunctive and why does French use it more than English?
What is the difference between a direct object pronoun and an indirect object pronoun?
How can I tell the difference between the imperfect/pluperfect/perfect tenses? When do I use them?
I don't understand the difference between Direct and Indirect Object Pronouns - how do I use them?