"à Pâques ou à la Trinité"

There is a French expression that I have been thinking of lately, "à Pâques ou à la Trinité". It means "at some indeterminate time, and possibly never". That seems to me an adequate description of the date at which journal submission reviewers turn in their reports. The expression comes from an 18t century song about Lord Malborough who went to war, his lady is waiting for him to return, he never comes back, then is heard to have died at war, and she changes her clothes to black mourning. A manuscript gets sent to a reviewer like a soldier gets sent to war: we hope that one day it will come back, in not too long, but we can never be entirely sure.