When the caretaker will unlock the gate, the runners enter the park.
We wait in the lobby until the technician will finish tomorrow.
Before the market will close, I will collect the repaired clock.
When the parcel arrives tomorrow, I will message you.✓Correct answer
Explanation
The parcel sentence keeps will in the main clause and uses the present simple after when, which is the standard future-time-clause pattern. The other sentences either put will inside the time clause or reverse the pattern by leaving the main clause in the present.