In the narration of Ibn Abi al-Zinad (may Allah have mercy on him) it is: "When it is lost."
It has also been narrated with the first wording from Ibn Abi al-Zinad, from Musa bin Uqbah, from Abu al-Zubayr, from Ibn Umar in marfu' form (attributed to the Prophet), but its chain is da'if (weak).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 10260