Wi-Fi help.

[Linux for blind general discussion]

Following the guide at
https://www.raspberrypi.org/documentation/configuration/wireless/wireless-cli.md,
I successfully got my Raspberry Pi 3 running a near stock Raspbian
Stretch Lite connected to my wireless network. Copying
/etc/wpa_supplicant/wpa_supplicant.conf and running wpa_cli -i wlan0
reconfigure, I repeated this on my Raspbery Pi 2 using a USB Wi-Fi
dongle without any effort.

Now, I'm trying to repeat this on a desktop that has Wi-Fi onboard
with much less success. I installed wpasupplicant and wireless-tools
via Aptitude, copied over the wpa_supplicant.conf file, and ran
wpa_cli -i wlan0 reconfigure to recieve the following error message:

Failed to connect to non-global ctrl_ifname: wlan0  error: No such
file or directory

And running iwconfig produces the following output:

wlan0     IEEE 802.11  ESSID:off/any
          Mode:Managed  Access Point: Not-Associated   Tx-Power=0 dBm
          Retry short limit:7   RTS thr:off   Fragment thr:off
          Power Management:off

Neither of which is all that helpful, especially since the above
mentioned successes with Raspberry Pis are the only successes I've
ever had connecting a Linux machine to a wireless network.

So, any ideas as to what I'm doing wrong?
-- 
Sincerely,

Jeffery Wright
President Emeritus, Nu Nu Chapter, Phi Theta Kappa.
Former Secretary, Student Government Association, College of the Albemarle.