Raw - definitely and always. And be sure to set the colour space of your camera to AdobeRGB, not sRGB. Shooting raw files in ARGB provides far greater latitude for processing. In other words, you can "play harder" without going out of bounds.
I always liken it to playing tennis with plenty of room around the court to run hard. JPEGs in sRGB, is like having cement walls right at the court boundaries, greatly limiting your swing!
As soon as is practical for you, move away from Elements and into Lightroom as, I believe, Elements is still somewhat limited to only a few functions working in 16-bit colour depth (still important, even with B&W as your files begin as colour files, or, at least should).
BTW, Lightroom has fantastic functionality for creating B&Ws and it can be purchased as a stand-alone, if you prefer not to be locked into Adobe's Creative Cloud leasing system.