Thanks Sniper and PErterAit
The fact that the drive is portable isn't completely irrelevant. At least, I would not say that. But, it is inconsequential when you know how to select it.
Lr says, at the top of the export dialog box, "choose: hard drive" then when you click open the drop down menu, it only adds CD/DVD. Now, I admit this was a mistake, but I took it to mean that my only choices were internal or CD/DVD. Even though a careful look at the choices after selecting hard drive would have also displayed any external storage devices connected (flash or any other USB device), I did not look closer which led me to the wrong conslusion that getting the image where I wanted it required some more intricate operation.
It may be a small thing, but words being as important as they are, I think the developers of Lr ought to consider changing the wording of selection "hard drive" which usually cannotes an internal device, to simply select "drive" or "storage media." Then, choose.
But, small thing. I have watched numerous vids about portions of Lr. Most exporting was to online media or to another editor. I am looking forward to more study over time.