There are expressions like “that moment when” and “me when…,” which have clear subordinate clauses and main clauses, and the main clauses are in apposition to the visual representation (e.g.
The problem with using quando or cum or si or some related word to render the “when” in such English expressions is that this “when” is introducing not a subordinate (temporal or conditional) clause, but a circumstantial statement in apposition to the visual representation presented.
