Master of Lore is not only a cost reducer that needs 3 rounds to justify its payment. It's an ally too. So even if it is an errata card it's always good to pay 3 for its multi-fonction nature : questing (with its 1 willpower or 1 defense in Siege mode), chump-blocking, or cost reducing (that can be increased by Leather Boots or Spare Hood and Cloak for instance). Plus, with its Gondor trait, he could benefit from Visionary Leadership bonus in some bi or tri-sphere Gondor deck.

Not much reviews neither comments, nor many questlogs but... come on ! Even in errata version, it remains a powerful and fun archetype, but absolutely not a no-brainer one (can be tricky, risky and eliminatory without planning !) Not a great variety on the cards choice for some optimal deck-building (mono , Arwen Undómiel, Círdan the Shipwright or Dáin Ironfoot, and / or Lothíriel, Prince Imrahil, Glorfindel, Jubayr) however that's mitigated by the randomness nature of the archetype itself : depending on the scenario, the moment and the allies of the Caldara's effect may change a lot. One can add even more surprise and (often) effectivness to Caldara's archetype with Dáin Ironfoot and The Burglar's Turn which is great against scenarios with early combat engagements.

If you play with ALEP cards, then you can have Box of Earth to make your Cloak of Lórien on Elrond almost as good as Gondorian Shield on Denethor or Beregond. Also, as previously mentioned, this is the only lore card with reliable defense. It also goes nicely alongside A Burning Brand.

In addition to the Thorongil options already mentioned, I like Fighting Merry in a Bond of Friendship deck to have Fast Hitch and gain the threat reduction from Hiding Merry. Denethor to Denethor with plenty of Unexpected Courage is always nice to make sure you use up all your activations when there wasn't much blocking in a given round. (As compared to nearly every other blocking hero, whose extra activations go to waste.)

Most of what needs to be said has already been said here, but I wanted to add two more targets: Prince Imrahil and Haleth. I'd also note that this attachment is more likely to find a juicy target when you're playing multiplayer, especially 4P.