Yeah, you're right about needing root (edit: for processes not owned by the current user). Though, if you have the access, it's a very, very worthwhile tool to learn:

  ~ $ lsof -a -n -c chrome -iTCP:443 | head -2 #sanitized output
  COMMAND   PID USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
  chrome   1234 me   12u  IPv4 12345      0t0  TCP 127.0.0.1:12345->127.0.0.2:https (ESTABLISHED)