Can the mitzvah of lechem mishneh, using two loaves, be fulfilled with a borrowed challah?

This source-based Torah study examines the question: Can the mitzvah of lechem mishneh, using two loaves, be fulfilled with a borrowed challah? The canonical Hebrew discussion develops the issue through the weekly Torah portion and the sources cited there, preserving the distinctions, tensions, and practical implications of the original text. This localized discovery layer does not add any new halakhic, medical, legal, scientific, historical, theological, or empirical ruling or claim beyond the canonical Hebrew source.