Aren't proxies only allowed if the card was damaged during the tournament? (For sanctioned tournaments of course)
That is correct.
EDIT - Even if the card is missing (lost during a sealed deck tournament, for example), you are not allowed to proxie it. The card is lost, the player will not be able to play with it, period. Players have to be careful with their cards.
The use of proxy cards is not permitted except under the following conditions:
§ If a card becomes accidentally damaged or excessively worn through play in the current DCI-sanctioned tournament, the judge may provide a proxy replacement card at his or her discretion or require the player to sleeve all of his or her cards before play continues.
§ If a card opened out of sealed product for use in a Limited tournament is misprinted, miscut, or otherwise damaged in a way that would cause the card to be marked, the judge may provide a proxy replacement card at his or her discretion.
There is no real answer to the question we can give by only seeing a picture of the card. Ask the HJ of your tournament and he'll have final authority on that (and no, he won't allow you to proxie it). If you want to have an answer now, just put the Lotus in a sleeve, add a dozen of other cards in the same sleeves, shuffle them, and try to see if you can find the Lotus while cutting. If yes, then the Lotus is not legal. If no, HJ opinion is needed...