English tip: the possessive ending " 's " carries an implicit "the".
(Except in constructs like “girls' school” or “a ten minutes' walk”.)
You're right about "girls' school", but "a ten minutes' walk" is wrong (should be "a ten-minute walk" or "ten minutes' walk").
If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Of course, for "every Monday", the last one should have been dated July 22-28. *cough*