Well, you should understand that Elements can do some things that are not in the "design model" of Lightroom, so it's always good to look at having either Elements or another capable "image/pixel editor" on hand so that after you have done your Raw processing in Lightroom )or Digital Photo Professional). Lightroom does extend the Raw processor you find in the full version of Photoshop CS5 and integrates it with very useful tools for organizing and outputting your images and, for many of us, does the great majority of what we do on our photos.
So, well, I'd get a handle on using Elements and, when you are ready to try something new get the trial of Lightroom. If you are shooting Raw, I'd advise you in the meantime to install Digital Photo Professional (DPP) the Canon Raw processor -- it is a good and quick way to whip out Raw images into good jpegs/tiffs that you can print, share on the Web or, if needed, open in Elements.
You mentioned price -- Elements retails at under $100 USD, Lightroom at a bit under $300 USD so that's where I suggest you take your time with Lightroom. If, though, you are a student or have one in your family/household then you can get a student discount for Adobe products, which brings the cost of Lightroom down to about $100 USD (don't know about Elements). That's a sweet deal!