If the Mrs is using regular arm warmer sleeves, she may want to add cooling sleeves to her repertoire. If you can get and keep them damp (water or sweat), I find they work better than my other so-called cooling gear.
Looking at the Tour schedule this week, we were thinking that you've got some big days coming up!
I was going to get her some cooling sleeves, though she is more using them for sun screen than cooling. I have no problem carrying enough water to keep them damp.
Yes, the next three days will be telling.
When I use them, it's partly for their usefulness as sunscreen too - same reason (among several) that I wear compression calf sleeves for running!