EDDiscovery is your friend (link in my sig)
You can have a journal view showing only the Rank journals (written with all your ranks when you log in) and filter it to exclude where the Explorer rank is not Elite then find the oldest one that remains.
Thanks for that. I've not used many of third-party apps but I think I'll use this one. Looks useful.
https://imgur.com/a/aOxRvTu
Here you go - screenshot.
