Is that latest-latest Raspbian, as in Raspbian Stretch released last week? It has some known networking issues that the Raspbian devs have been a bit coy about addressing.
The Foundation's current official response is along the lines of "It works if you set it up with keyboard and monitor", but if you're doing a headless setup, that doesn't help.
What worked for me was ensuring that
wpa-supplicant.conf had the following lines at the top, even if you're
working on the skeleton version copied from /boot
country=CA
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
Like all Raspberry Pi things, don't follow web advice more than a year old.
Working with anything other than Realtek USB wifi on a Raspberry Pi can be a crapshoot at the best of times.