Clue: Treat once penniless child — no fortune involved but it will cover the essentials (9)
Answer: LOINCLOTH
Explanation: Definition: it will cover the essentials
An envelope ('involved') of LOT ('fortune') in LOINCH, an anagram ('treat') of 'chil[d]' minus the D ('once penniless' – without D for the old Sterling penny) plus 'no'. After yesterday's CODPIECE, the definition was less obscure than it might otherwise have been.