Alleluia Haec dies quam fecit

Folio: 
001r
Sequence: 
1
Genre: 
Al
Position: 
1
Mode: 
?
Manuscript Reading Full Text (standardized spelling): 
Alleluia Haec dies quam fecit dominus exsultemus et laetemur in ea
Manuscript Reading Full Text (MS spelling): 
Alleluia Hec dies quam fecit dominus exultemus et letemur in ea
Indexing notes: 
006251c OR 006444b (Both are verses) How do I reflect the "Alleluia", is it part of the verse? Possibly still in the octave of Easter, although it could also be during the office of Easter itself.