Since "Shout Lula" seems to related to blues and work "hollers" perhaps the "Lula" originally refers to Lula, Mississippi or the Lula women from that town. Here's the lyrics to "Dry Well Blues" by Charlie Patton.   

Lyr. Add: DRY WELL BLUES

Way down in *Lula, hard livin' has done hit
Way down in Lula, hard livin' has done hit
Lord, your drought come an' caught us, an' parched up all the tree

Aw, she stays over in Lula, bid that ol' town goodbye
Stays in Lula, bidding you the town goodbye
'Fore I would come to know the day, oh, the Lula well was gone dry

Lord, there are citizens around Lula, aw, was doin' very well
Citizens around Lula, aw, was doin' very well
Now they're in hard luck together, 'cause rain don't pour nowhere

I ain't got no money and I sure ain't got no hope
I ain't got no money and I sure ain't got no hope
**....come in, furnished all the cotton and crops

Boy, they tell me the country, Lord, it'll make you cry
Lord, country, Lord, it'll make you cry
Most anybody, Lord, hasn't any water in the bayou3

Lord, the Lula womens, Lord, puttin' Lula young mens down
Lula men, oh, puttin' Lula men down
Lord, you outta been there, Lord, the womens all leavin' town

Notes: by Charley Patton,recording of 1929-1934, from "Charley Patton: Founder Of The Delta Blues" (Yazoo L-1020).


*At the time he recorded this song, Patton lived in Lula, Mississippi
** can't understand lyrics here.