Integration with photoshop

I'll start with your statement that "The photos are filed on my external drive". So they don't need to be 'uploaded' or copied somewhere else. However you want to 'manage' those files in order to find them easily, group them and finally 'edit' them to your taste. The solutions offered by either Lightroom and the Elements organizer are based on using 'catalogs', that is databases storing all the information about each of your photo/video files, the location (drive and path) on the computer, all the exif data, all your tags and captions, your albums or collections and indexing all that info for instant retrieval. No photo/videos files are copied or  duplicated;  only 'thumbnails' or small previews are created for fast visual browsing.

So, if you want to manage your photo library, you don't 'upload' if the file is already there on the computer, you "Import", which is not a good word to describe the process, I would rather say you 'index', you 'register' the data in the database. You can manage one or several catalogs, in Lightroom or the organizer, and from those catalogs, you can edit your photos in Lightroom, the Photoshop Elements editor, the full Photoshop or any other external image editor.

So, now, the question is about what software you want to use for your own needs. For instance, you could use Lightroom to manage your catalog(s) and edit your files in Lightroom, Photoshop, the Photoshop Elements editor or another software;  or you could use the Elements organizer to edit in the same above editors.

Generally, it does not make sense not to use the combo Lightroom and Photoshop if you have subscribed to that option, even if the Elements organizer and editor can both organize, manage and edit.

What can make sense is to use Lightroom alone for most of your jobs and use the Photoshop Elements editor when you need it; it's simpler than Photoshop and it has more tools for beginners. That's what was suggested in the first answers in this discussion.