(ql:quickload "clhs"). The ASDF system bundles a full copy of the CLHS (as permitted by LispWorks, with restrictions).
You'll then want to direct Emacs/Slime to use this newly installed copy of the CLHS, presumably. The wrapper can assist with this. Check the README for instructions. Long story short, after
(ql:quickload "clhs"), run
(clhs:print-emacs-setup-form) in the CL REPL and follow the instructions.
See the project's home for further information.
The "ASDF wrapper" part of this library is Public Domain, however the bundled CLHS is proprietary to Lispworks, so the overall product is very much non-free. See the LICENSE file for details.
The author of this library is not affiliated with LispWorks Ltd.