It's spelled 'Lisp'. There has been zero overlap between people writing "LISP" and people writing lisp code for about half a century.
Much like Fortran (no longer FORTRAN), the acronyms became proper names in their own right.
CL-USER 30 > (eq '|LISP| '|Lisp|)
NIL
Common Lisp knows very well the difference between LISP and Lisp