What you are suggesting is a workaround using authentication via the URL. I found that it did not work for me. 
Code:
http://user:asdfasdf@companyname.com/dav/user@companyname.com/Calendar
In firefox and thunderbird this brings up an authentication prompt, meaning that it did not read the username
assword from the url. So, this does not allow me to authenticate.
It is nice to have that solution on the same page though, just in case it does help someone. 
Hopefully some developers for Mozilla will vote for fixing the authentication issue in Thunderbird/Lightning with calendars,.. which would leave us without the need for these workarounds.

Originally Posted by
omegainstitute
I'm not 100% sure of that boardstretcher. You can feed user authentication into the URL as well. I wound up doing mine like:
Code:
http://user:password@domain.com/dav/user@domain.com/CalendarName
I've been able to add multiple users Calendar to my Lightning installation this way.