I have already done "pacman -Su", because whenever you post a question on an ArchLinux forum, someone always tells you to do a "pacman -Su". (I hate doing it, because I always have to rebuild the ZFS modules whenever the kernel changes.) So now you can answer the question without first telling me to do a "pacman -Su".

I've installed skypeforlinux, and whenever I try to make an outgoing call -- even the Skype Testing Call -- the call does not take place, and Skype logs me out. To anticipate a likely response (just as I anticipated that someone was going to tell me to run "pacman -Su") -- yes, I have tested the audio and video devices, they're fine. At least, they're fine as far as the Settings window is able to determine. But whenever I try to make an outgoing call, the next thing I know is that the large post-login window has been replaced by the small pre-login window, and I am being asked for my name and password again. Hopefully this is a known problem and I will not be asked for additional information, because there is little additional information I can give you.

Thank you in advance for any and all replies.

jay at m5 dot chicago dot il dot us

Shouldn't that be "pacman -Syu"?
I don't see how it's going to fix your connection problems, though.
Skype being closed source, there isn't much we can do.
What does the Arch wiki say about it?
Do you have other connection problems, too?

Try starting skype from a console and when it crashes see if there are any clues as to why on the console entry.
Sorry I've just tried the myself and it doesn't work.