I don't see Connectors offered on https://www.microfocus.com/en-us/products?trial=true
But I will double check with the product manager!
first of all, you need to have a valid contract with MF for ArcSight products acquired.
Second, the portal where you can download the ArcSight products acquired is: https://support.microfocus.com/downloads/swgrp.html
Once authenticated you need to introduce the SAID or Order Number to be recognized by MF portal and to be able to download the software products.