Isolation is a very modern meaning for Tower - adapted, perhaps, from the Rapunzel story? It almost negates the original Lenormand meaning.
Originally it meant a long and happy life (longevity or a "long view") unless "clouded" by negative cards. Scythe meant DANGER, peril. Literally it's a "danger to long life/longevity." I suggest Tower+Scythe can indicate something "cut short" (nearsightedness?) or cut down to size.
Another modern meaning is a large building, government or corporation (something BIG versus House, which is a smaller building): so we have down-sizing; undercutting; the fall of an official; a lease is up, etc.
Scythe+Tower could be a lengthy harvest (if Scythe's handle is on the right) or a big, long-lived danger (depending on the question and other cards). Also, government, corporate, official danger. For instance, harm done by fracking or a government bill that is cut.
Of course in daily spreads there can be far more literal meanings depending on the circumstances: cutting out intentions regarding a large (or official) building???