TotalFinder 1.1.9 introduced support for Lion.
We’re now at 1.4.18 and Mac OS X 10.7 Lion is still supported by TotalFinder. Along with Mac OS X 10.8 Mountain Lion, both will be supported for the foreseeable future.
Perhaps we’ll drop Lion support in January 2014, but that’s still up in the air.
Note that the last Mac OS X 10.6 Snow Leopard-compatible version is TotalFinder 1.3.4. Antonin wrote about it in this blog post last year.