Lookup in array based on weekday

My excel abilities are moderate, and I haven't used it for about a year, so apologies if this is a daft question.

I have a calendar spreadsheet that needs to lookup some information from an array. Both the calendar date and the array data are populated by a user from a userform.

I need to lookup information from the array, based on what day of the week is in a particular cell (but the day can be any weekday depending on what starting date the user entered). I started writing an 'IF' formula - 'if cell is a monday, take the info from this cell', but it occurred to me that even if that worked with 5 different ifs in every cell, there must be a more efficient way of doing this, perhaps with H or Vlookup.

Attached is a dummy of my problem, with the desired result on the second sheet in italics. Please could someone help me out? Thank you very much.