Saxy, I cannot hope to offer a better explanation than the one given in H's link above.
As regards Latin pronunciation in general, it is often said that it depends entirely upon how your own Classics master pronounced it! Some, for example, pronounce 'v' as 'w' and 'c' as 'ch', just to give two instances, where others use 'v' and 'k'.
Thus, we hear Caesar's famous words, "I came, I saw, I conquered"..."Veni, vidi, vici" as "Way nee, wee dee, wee kee" or "Way nee, wee dee, wee chee" or "Vay nee vee dee, vee chee" or "Vay nee, vee dee vee kee". Need I go on? The plain truth is that nobody - not even the Classics professors at Oxbridge - knows for sure how Latin was pronounced in Roman times.
In modern Italian, which may well be some sort of guide, we certainly hear the 'ch' sound in words such as 'la dolce vita'. Similarly, in Wilfred Owen's poem, Dulce et decorum est the 'c' in 'dulce' is generally pronounced 'ch', which is one variant of the soft sound.