I've written a page which describes a tactic that can be used to stop a loner in Euchre. Anyone who plays Euchre may want to take a look at that. What do you think?
It can be so frustrating when your opponent "goes alone" - you may feel like you should just give up. But a lot of loners are not certain, by any means. You should always play your cards as if you are defending against a loner that can be foiled. The page I linked to above is one of my thoughts about how to do it. I've seen it work many times!