However, I've forgotten how to turn on wifi networking from rescue mode.
Can anybody point me to a tutorial?
You could use the "iw" commands:
man iw
which should give you the info you need. "NAME iw - show / manipulate wireless devices and their configuration"
if you would like to review a tutorial:
http://linuxcommando.blogspot.com/2013/10/how-to-connect-to-wpawpa2-wifi-net...
has a decent write up if a bit dated. Should get you pointed in the right direction but everything still looks good on quick review.
HIH, Fred