Jeff,
I very recently treated the ends of some freshly cut Red Oak timbers with linseed oil. My timbers are covered, but unfortunitely, not hiding from the sun as well as I would like them to. Despite receving direct sunlight on the treated ends, they have yet to check in the least little bit.
I'd say it works quite well.
It seems reasonable to me, that if you plan to store the timbers for a prolonged peroid and they may receive sun exposure, to treat them again after cutting in the joints.
Shaun