Is the particle al- or el- at the start of an Arabic last name capitalized in a works-cited-list entry?

In general, no. The MLA’s guidance on Dutch particles applies to Arabic last names prefixed by al- and el- except that al- and el- are usually not capitalized in prose. In the example below, the author’s name appears as Jim al-Khalili in the prose but is listed under Kahlili in the works-cited-list entry:

Jim al-Khalili notes that “[o]n social media, we are more likely to engage with and trust content that aligns with our views. . . .”

Work Cited

Kahlili, Jim al-. “Doubt Is Essential for Scientists—but for Politicians, It’s a Sign of Weakness.” The Guardian, 21 Apr. 2020, www.theguardian.com/commentisfree/2020/apr/21/doubt-essential-science-politicians-coronavirus.

In its publications, if an author prefers that an Arabic name be listed under the particle—for example, because that’s how the name appears in the person’s book or on the person’s Web site—the MLA follows the author’s preference (e.g., Al-Kahlili, Jim instead of Kahlili, Jim al-).