Synonyms for Immediately upon:

• conj.

  •when (conjunction)
  • at,
  • while,
  • Albeit,
  • meanwhile,
  • although,
  • much as,
  • at same time,
  • Whereas,
  • Howbeit,
  • at the same time,
  • just as,
  • just after,
  • During.

• Other synonyms:

  •Other relevant words:
  • WHWN.