I have BW #32, and page 19 says this in the "Blues Forum" section conducted by Bob Groom:
205. Louise Johnson
The identity of the pianist on Louise's four Paramount sides continues to be a source of controversy. Rob Heath suggested in BW 29 that Louise accompanies herself on at leat one title while two of the four are quite definitely by Cripple Clarence Lofton. John Crosley makes the following comment on female blues pianists: Though Memphis Minnie, as well as a few other guitarists of my knowledge, played a quite masculine guitar, I have yet to have heard the same hold true in the case of the piano. Perhaps one of the best examples of a masculine-sounding pianist would be the Texas gal, Dot Rice, whose accomplishments on disc are admirable. Still, I simply cannot accept (after a lengthy listen) that she played with that powerful, reckless abandon characterised by a long list of male blues/boogie pianists who left no doubt as to their sex. Another example can be cited whose works are more readily obtainable than those of Dot, Hociel Thomas. Of the two Dot was certainly the more dominately male-sounding stylist. Not too many femalse were involved in the style of piano playing that could be readily associated with what we've learned to term 'funky, whorehouse'.
It seems unlikely that the argument will ever be resolved. Son House was indisputably present at the session but time can cloud the memory. Lofton apparently recalled the session in conversation with Crosley, but other evidence of his presence is non-existent. Even though Louis is known to have played piano, aurally I doubt that the pianist is the singer on these sides, but whether the pianist was Lofton is another question.
I am happy to make a pdf scan of this page and email it to you privately if you wish to have it.
I also trust you already have BW #29, the aforementioned Rob Heath article. It's a one-page analysis of the Louise's recordings. If you don't have it, let me know, I also have that one and can make it available to you.
Cheers!