Don't assume – test...
Make damn sure Arc is scriptable before doing anything.
If it is then you can go-to-town.
Here's a place to start:
Checking Whether a Given URL is Already Open in Google Chrome Tabs - #2 by peternlewis
There are a number of other macros on the forum that do this kind of thing.
Here's one:
Google Chrome – How to Bring an Existing GMail Tab to the Front - #11 by ccstone