Supergirl's series, which was about the same size, is canonical. So I guess the final determination would be whether Black Lightning could be considered a "Superman family" title or not. For this standard, the first Supergirl series could be used: While it was the only Superman Family title to actually have a member of Superman's family in it, it was published in the 70s, ran for only 10 issues, and took place in a Metropolis suburb, with characters that do not appear in other canonical sources.
First, let's take a look at Black Lightning's chronology as a character.
He first appeared in
Black Lightning #1.
Inspector Henderson appeared in issue #3, with Clark Kent interviewing him for WGBS. Issue #4 is a Jimmy Olsen issue, where Olsen is treated as Black Lightning's equal. Officer Corrigan and Superman also appear in this issue.
Issue #5 is titled "Nobody Beats a Superman." In this issue, Black Lightning justifies why he is needed in a city that already has Superman, after the two converse and then face off against the Cyclotronic Man.
In issue #7, there is a big new revelation about Inspector Henderson's son.
(Issues #1-8 are generally considered one complete arc.)
Issue #11 was the last, and was written by Dennis O'Neil. O'Neil then continued the series in World's Finest #256-#261. During this time, Black Lightning also appeared with Superman in DC Comics Presents #16 and in two issues of Justice League for America, where he rejected League membership.
Supergirl #1-10 is considered canonical for SUPERMANica. Superman never appears in this book, (though Kandor shows up once,) yet Superman and related characters appear throughout the Black Lightning series (nearly 50% more, in fact
)
LINKAGE?Last Son of Krypton is considered Canonical in Supermanica because two comics refer to the novel
Miracle Monday, which then refers to it. The linkage of
Black Lightning to the canonical sources is much more direct. O'Neil's Black Lightning stories in World's Finest (a canonical source even by TGSB standards) refer to the
Black Lightning series, and continue directly from those issues.
Black Lightning's first 20 appearances in the comics are Superman-related: Black Lightning #1-11, World's Finest #256-259, DC Comics Presents #16, JLA #173-174, and World's Finest #260-261. He was thus, in the 1970s, a Superman character. After 1980 he became more closely associated with Batman, appearing in Detective Comics, joining the Outsiders, and coming back for two more issues of World's Finest...but then again, Batman is fairly welcome in Supermanica as well.
That's all for now! Sources used in my research:
http://www.dcuguide.com/chronology.php?name=blacklightning2http://www.dcuguide.com/chronology.php?name=supergirlprechttp://www.comictreadmill.com/CTMBlogarchives/2005/2005_Monthly/2005_03.php