What case is marked on the last component of «جَاءَنِي بَعْلَبَكُّ»?

Al-Murakkabāt — Compound Numerals, the Twelve Exception and Declining Baalbek

• Genitive with fatḥah
• Accusative with fatḥah
• Built on sukūn
• Nominative with ḍammah; the whole name is subject