Go to Lightroom Preferences> General tab> Import dialog
Select "Show import dialog when a memory card is detected".
Thanks for the suggestion, but I had already tried that.
I had checked "Show Import dialog when a memory card is detected." But Image Capture opens when a card is detected, not LR. What do I need to do to change that?
I would suggest you see how you can turn that option off in "Image Capture". I have an MacBook Pro but do not use iPhoto so I have no idea.
I also don't use iPhoto. (Indeed, once in a while I think there is some need for it and discover it requires Silverlight which is a Microsoft product that has reportedly security issues and in the past didn't even download properly. Also iPhoto wants priority.)
I would like to try your suggestion, but I can't find any option in "Image Capture" that allows me to turn off anything related what happens when a card is detected. Perhaps I should try an Apple discussion.
This time I lucked on the right Apple discussion and the answer at:
Apparently, the first time a new camera or card is inserted, Image Capture will open. You can then use this obscure way to change the Mac OS instructions so that for that camera or card, Lightroom will open instead. I just tried - and it worked.
Thanks DdeGannes for your efforts.