Here is a game where my opponent could not remove enough of my elves and I was able to have a permanent cycle.
My opponent was able to gain a ton of life with Sangromancer.
"Whenever a creature an opponent controls dies, you may gain 3 life.
Whenever an opponent discards a card, you may gain 3 life."
He/she had two of these and they are flyers. This was my opponent's only way to exact damage against my legion of elves.
I was low in life and near milling myself when Elixir of Immortality put me back to a full deck and with a little more life.
Both of my Slate of Ancestry are on the board.
Once I play Nissa I can start gaining life for every elf I control.
At some point my opponent gave up. I was about to gain a ton of life, and about to hit with a legion of elves, two soul-bonded Wolfir Silverhearts, and two Wurmcoil Engines.