Why is “huwa mubtasim” circumstantial in “jāʾa Khālidun wa-huwa mubtasim”?

Supplementary Practice 6: Rhetorical Dialogue, Responding to Objections and Choosing the Right Expression

• It reports a different person’s arrival
• It restricts the agent
• Wāw always coordinates independent reports
• The pronoun refers to Khalid and describes his state on arrival