Does the Hawl (lunar year) for Zakat on money begin from the time the salary becomes due, or from the time it is actually received after six months?

Zakat is obligatory on one who owns the nisab and a hawl (lunar year) has passed on it (85 grams of gold or 595 grams of silver, and the passage of one lunar year). The hawl begins from the moment one owns the nisab. A delayed employee salary is considered a debt; if it is owed by a solvent person (one who acknowledges the debt and is able to pay), then zakat is paid on it as if the money is in hand. If it is owed by an insolvent person or one who procrastinates, then there is no zakat until the money is received and one hawl passes from the date of its receipt.