When you start your Surface Pro2, your Arc Touch Mouse works perfectly.
After awhile, it stops working. To recover the Mouse and make it work again
you have to turn the power of the Arc Touch Mouse off and turn it on again. That helps for awhile, then it stops working again.
When the Arc Touch Mouse stops working you can see the light of the Arc Touch Mouse is still on.
In order to avoid this behavior you should follow the following steps:
Disable power setting from "device manger"-->"Bluetooth"-->"Marvel Avastar Bluetooth Radio Adaptor"-->"Power Management"-->Uncheck "allow the computer to turn off this device to save power"
I hope this helps