In an index or sortable list of titles, MLA style follows the The Chicago Manual of Style, which recommends placing initial articles at the end of the full title (16.51). A Tale of Two Cities would appear as Tale of Two Cities, A. Note that titles in indexes do not include subtitles unless they are “essential for identification” (16.55). If a subtitle is included, the initial article should be placed at the end of the full title, not before the subtitle. 

In both indexes and works-cited lists, MLA style uses letter-by-letter alphabetization (MLA Handbook 2.7.1.). Note also that in works-cited lists MLA style would not move the initial article but would still ignore it for the purposes of alphabetization (see the works-cited list below for an example).

Works Cited

The Chicago Manual of Style. 17th ed., U of Chicago P, 2017.

MLA Handbook. 8th ed., Modern Language Association of America, 2016.