The edismax lowercaseOperators=false option seems to have been broken by
SOLR-3026. "foo and bar" and "foo or bar" are treated as "foo AND bar" and "foo OR bar", respectively, even when lowercaseOperators=false.
Fix is rather simple, I think (though I haven't tested this). Current code:
Also interesting is the treatment of "Or" and "oR", but I'll leave that as an exercise to the reader.