Elven Chorus — ruling 1

You'll still pay all costs for the spell, including additional costs. You may also pay alternative costs if any are available.

Elven Chorus — ruling 2

Elven Chorus doesn't change when you can cast creature spells. Normally, this means during your main phase when the stack is empty, although flash may change this.

Elven Chorus — ruling 3

The top card of your library isn't in your hand, so you can't take other actions that would normally be allowed from your hand, such as discarding it due to an effect or activating a cycling ability.

Elven Chorus — ruling 4

If the top card of your library changes while you're casting a spell, playing a land, or activating an ability, you can't look at the new top card until you finish doing so. This means that if you cast a spell from the top of your library, you can't look at the next one until you're done paying for that spell.

Elven Chorus — ruling 5

You can look at the top card of your library whenever you want (with one restriction; see below), even if you don't have priority. This action doesn't use the stack. Knowing what that card is becomes part of the information you have access to, just like you can look at the cards in your hand.

Elven Chorus : règles, fonctionnement et interactions (MTG)

Elven Chorus is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

You may look at the top card of your library any time. You may cast creature spells from the top of your library. Creatures you control have ": Add one mana of any color."

How it works : Elven Chorus

Original English text — Wizards of the Coast / Scryfall

#1June 16, 2023· Wizards of the Coast
You'll still pay all costs for the spell, including additional costs. You may also pay alternative costs if any are available.
No other card is named in this ruling.
#2June 16, 2023· Wizards of the Coast
Elven Chorus doesn't change when you can cast creature spells. Normally, this means during your main phase when the stack is empty, although flash may change this.
No other card is named in this ruling.
#3June 16, 2023· Wizards of the Coast
The top card of your library isn't in your hand, so you can't take other actions that would normally be allowed from your hand, such as discarding it due to an effect or activating a cycling ability.
No other card is named in this ruling.
#4June 16, 2023· Wizards of the Coast
If the top card of your library changes while you're casting a spell, playing a land, or activating an ability, you can't look at the new top card until you finish doing so. This means that if you cast a spell from the top of your library, you can't look at the next one until you're done paying for that spell.
No other card is named in this ruling.
#5June 16, 2023· Wizards of the Coast
You can look at the top card of your library whenever you want (with one restriction; see below), even if you don't have priority. This action doesn't use the stack. Knowing what that card is becomes part of the information you have access to, just like you can look at the cards in your hand.
No other card is named in this ruling.