I have exactly the same problem with a 7260 AC on a Dell Latitude E7440. Dear Intel Engineers, here's how to reproduce the issue:
1) buy a Dell Latitufe E7440
2) put it into standby (suspend to ram)
3) wake laptop up after 8 hours at work
4) enjoy the lack of internet
The workaround is the same as many people describe: disable the network adapter (in the hardware manager for example), enable it again, and after 2 seconds you have Wifi again.
If only I had Linux installed on this laptop, I could let you know whether it's a hardware issue or a driver issue.