How to connect originals to library after library file lost?

Hi there,

I have a Lightroom CC library with baout 90k photos in it.

I had all the originals photos both in the cloud and on an external hard drive, but the Lightroom library file was on my old laptop.

That laptop was destroyed. 

No I've got a new one and installed Lightroom on it. 

I'd like to connect all my old local orginals on my external HD to my library. But under preferences when I tell it the correct location for "storage location for originals" it just creates a new folder structure there and downloads all the originals all over again.

Now, I could just go through all that again, but it seems like a waste of time and bandwidth. Is there some way to have Lightroom recognise the existing originals? 

It seems to me the problem is that I don't have the old Lightroom library file, which must have told lightroom where all the originals are.

I'm running Lighroom 5.4 on Mac OS X 12.2.1.