These Ruling(s) have not been confirmed as applicable to the TCG.[Notes 1]
Summoning "Lava Golem" makes it so that player is unable to Normal Summon for the turn. Similar to how if your Normal Summon gets negated, you are still unable to perform another Normal Summon for the turn, the same applies to the Special Summoning of "Lava Golem".
Shining Elf: When your opponent Special Summons "Lava Golem" to your side of the field, it is still treated as your opponent Special Summoning a monster, so you can activate the effect of "Shining Elf".
Previously Official Rulings
These TCG rulings were issued by Upper Deck Entertainment and have since been deemed unofficial by Konami. They were previously considered official and can still be correct, as long as they follow the official gameplay rules, or unless Konami has issued a ruling that says otherwise. References: 
"Lava Golem" must be Special Summoned to your opponent's side of the field using its effect text; you cannot Special Summon it or Tribute Summon it to your side of the field.
However, if Special Summoned correctly and then sent to the Graveyard, you can use "Monster Reborn" to Special Summon "Lava Golem" to your side of the field, but you (as the controller) will then take the 1000 damage during your Standby Phases.
You cannot Summon or Set and then Special Summon Lava Golem.
↑Konami Judge Program Rulings are considered unverified, as their source(s) are not publicly viewable. They are not confirmed as applicable to the TCG until they have been officially published by Konami.