I recently upgraded my photoshop elements and now I cannot find where the "blend if" tool is located. It use to be within FX effects at the bottom of the layer column on the lefthand side. Using it to colorize B&W photos. Pictured is the old set up of where to find it.
Just to add to @MichelBParis 's post (which is absolutely correct), there is a third-party add-on product for Adobe Photoshop Elements called Elements+ which features a Styles dialog box that includes the Blend If option. It is very reasonably-priced, has a ton of other features, and the product & author are very well-regarded in the Photoshop Elements community: